leucism

noun leu·cism \ ˈlü-ˌsi-zəm \

Definition of leucism

: an abnormal condition of reduced pigmentation affecting various animals (such as birds, mammals, and reptiles) that is marked by overall pale color or patches of reduced coloring and is caused by a genetic mutation which inhibits melanin and other pigments from being deposited in feathers, hair, or skin

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leucistic

play \lü-ˈsi-stik\ adjective

Recent Examples of leucism from the Web

Most animals feature a range of color variations, including albinism (an absence of pigment) and leucism (a partial loss of pigmentation).

— paul a. smith, Milwaukee Journal Sentinel, "Wisconsin man encounters rare white deer fawn on Sauk County morel mushroom hunt," 15 May 2018
The white giraffes displayed the characteristics of a genetic condition known as leucism, which inhibits pigmentation in skin cells, Dr. Ali said.

— yonette joseph, New York Times, "Rare White Giraffes Cause a Stir in Kenya," 16 Sep. 2017
The giraffes' white color is caused by a genetic condition called leucism that affects their cells' pigmentation, the Program said.

— rachel lewis, Time, "Wildlife Experts Spotted a Rare All-White Giraffe and Her Cub in the Wild," 18 Sep. 2017
Animals with leucism may have darker pigment in their soft tissue, and their eyes retain a normal color.

— yonette joseph, New York Times, "Rare White Giraffes Cause a Stir in Kenya," 16 Sep. 2017
Despite their inability to produce colorful pigment, giraffes and other animals with leucism don’t face genetic disadvantages to their survival, but their color can attract unwanted attention.

— National Geographic, "Why These Giraffes Are Completely White," 14 Sep. 2017
Life can be tough for white squirrels, and other animals with leucism.

— joan morris, The Mercury News, "Unusual white squirrel seen cavorting in Walnut Creek," 11 Apr. 2017
There are three ways this can occur: albinism, leucism, and isabellinism.

— National Geographic, "Pictures: Rare White Giraffe and Other Unusually Pale Animals," 28 Jan. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'leucism.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.